I don't have any additional spaces in my electrical panel and want to add a 20 amp garage circuit. The laundry has a 20 amp. Can I replace that breaker with a two circuit breaker meant to fit in the same space? Is this what is called a piggyback breaker? What restrictions are there on replacing a breaker with this type of breaker that takes up the same space but has two breakers? Appreciate any help on this. Dave